1. Field of the Invention
The present invention relates to a semiconductor device for use in an inverter circuit for driving a motor or the like.
2. Description of the Related Art
A semiconductor device in which a transistor element such as a metal oxide semiconductor field effect transistor (MOSFET) element or an insulated gate bipolar transistor (IGBT) element is formed is known as a semiconductor device for use in an inverter circuit for driving a motor or the like. The semiconductor device according to the related art in which the MOSFET element is formed has a rectangular shape as viewed in plan. A source pad and a gate pad are formed on one surface of the semiconductor device. A drain electrode is formed on the other surface of the semiconductor device. The source pad is formed so as to cover substantially the entire surface of the semiconductor device. The gate pad is formed at one corner portion of the surface of the semiconductor device, or at the center portion of an edge portion along one side of the surface of the semiconductor device.
A plurality of unit cells that each compose an MOSFET element are disposed in a matrix inside the semiconductor device. A gate electrode corresponding to the plurality of unit cells is disposed in a grid so as to surround the center portion of the unit cells. A portion of the gate electrode that is proximate to the gate pad is electrically connected to the gate pad (see Japanese Patent Application Publication No. 2001-102576 (JP 2001-102576 A), Japanese Patent Application Publication No. 2005-33073 (JP 2005-33073 A), Japanese Examined Patent Application Publication No. 5-63098 (JP 5-63098 B), and Japanese Patent Application Publication No. 2009-64995 (JP 2009-64995 A)).
In the semiconductor device according to the related art discussed above, the time for propagation of a gate input signal to the unit cells that are distant from the gate pad is long, and therefore the time of delay in output in response to the gate input signal is long.